As a liquid organopolysiloxane having a hydrophilic group and a crosslinking portion, a product obtained by reacting a particular alkylene oxide derivative, a particular silicone derivative, and a particular isocyanate compound has been reported as being excellent as an industrial use anti-foaming agent (see Patent Document 1). However, this material uses an isocyanate, which has high hazardous properties, as a raw material. Therefore, from the perspectives of safety, cost for refinement, and the like, there are obstacles in using such a material.
Additionally, as a liquid organopolysiloxane having a hydrophilic group and a crosslinking portion, an organopolysiloxane-polyoxyalkylene in which at least two organopolysiloxane-polyoxyalkylene molecules are crosslinked using a crosslinking compound free of internal hydrolysable bonds is disclosed. It is also reported that such a liquid organopolysiloxane is useful as an emulsifier (Patent Document 2). A great deal of applied research regarding this material has been conducted and the following technologies have been reported: a polar liquid in nonpolar liquid emulsion (Patent Document 3); a vaseline-containing emulsion free of oily stickiness (Patent Document 4); a hair conditioning composition (Patent Document 5); and a defoaming composition and a silicone anti-foaming composition (Patent Documents 6 and 7).
However, while the material proposed in Patent Document 2 has excellent characteristics for emulsifying/dispersing water in a hydrocarbon oil, ester oil, or similar non-silicone oil, water cannot be stably emulsified/dispersed in a system containing a large amount of silicone oil. Furthermore, when the obtained emulsion is stored for an extended period of time, there is a problem in that the emulsion produces an odor.
On the other hand, a polysiloxane-polyether base copolymer comprising a T unit and random bonded organopolysiloxane units and straight polyether units in which the organopolysiloxane and the polyether units are bonded via Si—O—C or Si—C bonds is disclosed (Patent Document 8). It is reported that such a copolymer has improved characteristics as a lacquer coating additive. However, this material is manufactured according to a method in which a straight alkenyl-containing polyether having a terminal OH group is added via hydrosilylation to an organopolysiloxane having a Si—H group. Then, the remaining Si—H groups and the terminal OH groups of the polyether portion bonded to the siloxane are condensed by dehydrogenation in the presence of a strong base. As a result, disconnecting of the organopolysiloxane portion caused by the strong base occurs easily, and achieving constant quality and performance is difficult. Additionally, because the crosslinked portions contain Si—O—C bonds, there is a problem in that hydrolysis occurs when compounded in a formulation including water, which leads to a gradual decline in effectiveness.
As a hydrolysis resistant liquid organopolysiloxane having a hydrophilic group and a crosslinking portion, a polyether-polysiloxane-copolymer that has alkylene groups having from 2 to 10 carbons at both terminals, and that is crosslinked by a polyether in which a free valence of said group is further bonded to one silicon atom of the copolymer (Patent Document 9); and a branched polyether-polysiloxane-copolymer having a constituent expressed by the general formula: Y[—CnH2n—(R2SiO)m-Ap-R2Si-G]x (Patent Document 10) are known. Additionally, a polysiloxane copolymer is disclosed that can be manufactured by reacting an organopolysiloxane having at least one Si—H bond per molecule with a substantially linear compound that is addable via hydrosilylation and, thereafter, further reacting with an organic compound having at least two isocyanate groups per molecule (Patent Document 11). Furthermore, a surfactant comprising a crosslinked body of an active hydrogen-containing modified silicone and a crosslinking agent, wherein the viscosity (at 25° C.) of the crosslinked body is from 500 to 100,000,000 mPa·s is reported (Patent Document 12). However, applicable fields of this material are primarily limited to anti-foaming agents, and use as a cosmetic composition is not reported.
Additionally, as technologies related to a liquid organopolysiloxane having a hydrophilic group and a crosslinking portion, organohydrogen silicon compounds comprising at least one silicon-bonded hydrogen atom and at least one cyclosiloxane ring per molecule; and applications as a curable composition for paper coating are reported (Patent Documents 13 to 16). However, in these citations, there is no recitation about liquid types in which the hydrophilic group is modified or applications in cosmetic composition.
As described above, materials used in the field of cosmetic compositions as liquid organopolysiloxanes having a hydrophilic group and a crosslinking portion are limited to only the organopolysiloxane-polyoxyalkylene recited in Patent Document 2, and there is a need to solve the various problems thereof.
Now, a great deal of research into reducing the odor of polyether modified polysiloxanes that do not have crosslinking portions (polyoxyalkylene group-containing organopolysiloxanes) has been conducted. The first cause of odorization over time of a polyether modified polysiloxane that was reported was the aldehyde and acid produced as a result of oxidation degradation (rancidity) over time of the polyether moiety in the polyether modified polysiloxane composition. Examples of technologies to suppress this oxidation degradation include the methods recited in Patent Documents 17 and 18 in which tocopherol, phytic acid, or a similar anitioxidant component is added to the polyether modified polysiloxane composition.
However, the use of only an anti-oxidizing agent results in the insufficient suppression of the odorization over time of a formulation based on the polyether modified polysiloxane and, as a result, other causes were investigated. As a result, Patent Document 19 recites that propionaldehyde originating from unreacted propenyl-etherified polyoxyalkylene is a cause of the odor.
The polyether modified polysiloxane composition is typically synthesized via a hydrosilylation reaction of an organohydrogenpolysiloxane having a silicon-bonded hydrogen group and a polyoxyalkylene having an allyl ether group at a terminal. Patent Document 19 recites that, in the production of the polyether modified polysiloxane composition, a double bond of the allyl etherified polyoxyalkylene migrates inward due to the influence of a platinum catalyst and a portion of the allyl-etherified polyoxyalkylene becomes a propenyl-etherified polyoxyalkylene and remains in the polyether modified polysiloxane composition as-is without reacting with the organohydrogenpolysiloxane. Patent Document 19 also recites that the propenyl-etherified polyoxyalkylene degrades over time, thus producing ketones and aldehydes which results in the odorization. Moreover, hydrolysis in the presence of an acid is disclosed as a useful deodorization method.
However, while this deodorization method could be thought to be useful if all of the allyl groups of the polyoxyalkylene remaining in the composition were replaced with propenyl groups, in actuality, a significant proportion of the allyl-etherified polyoxyalkylene which is not easily hydrolyzed remains. As a result, the composition cannot be sufficiently deodorized using the deodorization method of Patent Document 19. On the other hand, if a strong acid is used that can hydrolyze the allyl-etherified polyoxyalkylene, the carbon-oxygen bond at the polyoxyalkylene site and/or the silicon-oxygen bond at the polysiloxane site may disconnect, so using such an acid is inappropriate. Additionally, in order to perform the hydrolysis reaction in a quantitative manner, excessive amounts of water and acid are needed. These excessive amounts of water and acid complicate post treatment processes and, therefore, this deodorization method is not preferable.
In order to resolve this problem, methods for suppressing the production of propionaldehyde have been disclosed (Patent Documents 20 to 23). In these methods, a hydrogenation treatment is performed as a deodorization method of the polyether modified polysiloxane composition in order to alkylate the alkenyl groups (double bonds) included in the alkenyl group-containing polyoxyalkylene (including both propenyl-etherified polyoxyalkylene and allyl-etherified polyoxyalkylene) remaining in the composition. However, even with a polyether modified polysiloxane composition deodorized using a hydrogenation reaction, in cases where a formulation including water and an alcohol is compounded, it may be difficult to achieve sufficient deodorization over time or under elevated temperature conditions.
A cause of the odorization is acetal and similar aldehyde condensation products that are free of unsaturated bonds that remain in the composition. Thus, for the purpose of completely eliminating the acetal and other aldehyde condensation products, technology in which treatment using the acid aqueous solution and hydrogenation treatment are combined (Patent Document 24); and technologies in which hydrogenation treatment and treatment using a solid acid catalyst are combined (Patent Documents 25 and 26) are disclosed. The technology recited in Patent Document 24 is applied not only to polyether-modified silicones, but also to glycerin-modified silicones and sugar-modified silicones. That is, it is acknowledged that performing at least hydrogenation treatment is preferable in the deodorization of hydrophilic silicones exemplified by polyether modified polysiloxane, which is a raw material suitable for use in cosmetic products.
On the other hand, Patent Documents 27 to 40 recite technologies related to glycerin-modified silicones that do not have crosslinked portions, and application to these types of cosmetic compositions has been heavily researched. Recently, it has been thought that glycerin-modified silicone was superior to polyether-modified silicone from the perspective of oxidation stability and, thus, glycerin-modified silicone has attracted attention as a surfactant having greater safety. For example, in Germany, a demand for the replacement of raw materials having polyether groups with non-polyether raw materials has increased due to a negative perception of the safety of products comprising polyoxyethylene (PEG) due to testing done by a consumer information magazine company. Moreover, in South Korea, increased interest in non-polyether silicone surfactants has emerged due to a concern that products containing polyoxyethylene (PEG) may irritate the skin because formalin may be produced as a result of oxidation degradation of PEG.
In light of the above, there is a global trend toward changing the entire formulation of end consumer products such as cosmetic products, and the like, to PEG-FREE formulations. In concord with this trend, there is a demand for progression from the old polyether-modified silicone technology to non-polyether hydrophilic silicone in the field of silicone-based surfactants as well. However, conventional glycerin-modified silicone have significant problems in that they do not appear in patent document searches. This is because even if glycerin-modified silicone is used as an emulsifier for a water-in-oil emulsion, it cannot be used in an actual formulation because performance is low. As a result, there is no choice but to use a more reliable polyether-modified silicone emulsifier in combination with the glycerin-modified silicone, which makes it impossible to achieve the goal of shifting all cosmetic compositions to PEG-FREE formulations.
However, a liquid organopolysiloxane having a glycerin derivative group and a crosslinking portion in which the crosslinking portion links the organopolysiloxane portion and the organic portion via a Si—C bond has not been disclosed, and use of the same in cosmetic compositions and external use preparations is not known.